This invention relates to a portable riser usable by choral groups either singly or in combination with other risers as well as by other groups including bands and orchestras.
The prior art has structures for stands or risers which can be moved between a storage position and an erect position for use. A structure of this type is shown in Ellis U.S. Pat. No. 2,598,983. The stand of this patent has no specific structure for portability and does not have an arrangement whereby the steps may be moved into a superimposed relation for travel.
The Mackintosh U.S. Pat. No. 2,859,488 discloses a stand with steps movable between a storage position and an erected position and has casters for portability. However, it is necessary to physically turn the entire unit between a position wherein the casters engage the floor and a position whereby the stand may be erected.
The Berg U.S. Pat. No. 3,229,430 discloses a choir riser wherein a plurality of steps are in superimposed relation for storage and which may be opened out and then the stand erected for use. There is no disclosure of structure facilitating portability of the unit, such as casters movable along a floor. Additionally, the structure of this patent requires turning of the entire unit to an upside down position in order to move the riser components between a storage position and an erected position.
The assignee of this application has U.S. Pat. Nos. 3,747,706 and 3,747,708 relating to a portable riser. In the structures of these patents, it is necessary to turn the riser between a travel position and a position for erection. These patents also show an optionally usable fourth step and the first of these patents shows a guard rail hinged to the unit for positioning at a level above and to the rear of the uppermost step.